The present invention relates to a device transferring method of transferring devices such as semiconductor light emitting devices, a device arraying method of re-arraying devices, each having a fine structure, densely arrayed such that the devices are enlargedly spaced from each other by making use of the device transferring method, and an image display unit fabrication method making use of the device arraying method.
Methods of transferring or arraying devices are known. One of these methods involves dicing a wafer to isolate devices from each other, transferring the isolated devices from a dicing sheet to a chip tray, and picking up the devices (for example, semiconductor chips) from the chip tray by vacuum attraction to mount or connect the devices to a substrate. This method is generally carried out during a process of fabricating semiconductor packages. This method, however, requires the step of transferring and mounting the devices one by one, and is not appropriate for arraying a large number of devices.
To array a number of devices, there are known methods of directly mounting devices, each having a fine structure, on a substrate, as disclosed in Japanese Patent Laid-open No. Hei 9-120934. According to this method, recesses corresponding to an array pattern of devices are previously formed in the substrate, and a slurry in which devices are dispersed in a liquid are made to flow on the substrate so as to be put in the recesses formed in the substrate, whereby the devices are arrayed on the substrate. Such a method, however, has disadvantages in that a number of devices larger than that of the recesses must be prepared and it takes a long time for the devices to be put in the recesses, thereby requiring a long time until the device arraying step is completed. Further, the recesses must be formed at a high accuracy when arraying the devices on a large substrate and a large-sized apparatus capable of containing a substrate is required to form the recesses in the substrate. These disadvantages are amplified when smoothly arraying devices on a substrate.
For example, when arraying light emitting devices in a matrix to fabricate an image display unit, a technique to efficiently transfer and array a large number of devices while carrying a distance for each of the devices is essential. Accordingly, a need exists for an improved device transferring method and an improved device arraying method.